I was unfamiliar with "the gray rock approach", so I looked it up. According to Medical News Today at https://www.medicalnewstoday.com/articles/grey-rock,
The grey rock method is a tactic some people use when dealing with abusive or manipulative behavior. It involves becoming as uninteresting and unengaged as possible so that the abusive person loses interest.
Some people anecdotally report that it reduces conflict and abuse.
The idea behind the technique is that abusive people, especially those with narcissistic tendencies, enjoy getting a reaction from their victims. Refusing to give them this reaction makes interactions less rewarding. There is no research to confirm that it works.
Confusing transgender actions with physical and/or emotional abuse sounds about right for a TERF bigot. And remember, there's no evidence that acting like a "gray rock" actually achieves anything.